Pretty much. The vendor when obtaining his license got a tax ID and became obligated to pay revenue because the vendor is gaining. From what I have gathered, its the vendor that is obligated to pay the sales tax not the purchaser nor the consumer. But somehow, perhaps through conditioning, the vendor has passed it on to the consumer. However, I recall seeing regulations (pertinent to some venue) which prohibit seller's from building the tax into the price. The same might apply to income tax only during the 60s or so they figured out a way to make the employee pay the tax. I am unaware of any U.S. State that doesn't have a form for applying for a sales/use tax exemption certificate!
Perhaps what they decided to do was presume "everyone" to be a stranger.
I tend to see the letter to be honest even if the wording might be carefully construed. At the same time, technically, a blank check doesn't have monetary value either. Not to suggest a birth certificate to be a 'blank check', but for perspectives illustrating the point as to how something like a blank check, rightfully signed and even associated with a billion dollar bank account can be said to have no monetary value and it be very true.
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On that note, couldn't someone simply send the birth certificate and social security card back with a resignation letter rather than go through all of that UCC filing stuff?